Method of manufacturing drill-bits.



s. v. RAWLINGS. METHOD OF MANUFACTURiNG DRILL BITS. APPLICATION FILED JUNE 6; I910- LQQJYQO. Patented June 12, 1917.

SAMUEL v. nAwLrnGs, on CALUMET, MICHIGAN.

V METHOD OF MANUFACTURING DRILL-BITS.

Specification of Letters Patent.

Patented June 12, 1917.

Application filed June 6, 1 910. Seria1No..565,196.

To all whom it mayconcern:

Be it known that I, SAMUEL V. RAWLINGS, a citizen of the Unitecl,States,.and a resident of Calumet, Michigan, have invented certain new and useful Improvements in Methods of Manufacturing Drill-Bits, of which the following is a description.

The improvement relates to drill bits having flaring cross wings upon which the shaped cutting edges are formed, and the invention seeks to provide an improved method of manufacture whereby the bit is of great strength and durability and has lasting cutting qualities.

The invention consists in the features of improvement hereinafter set forth, and more in position upon the supporting plate of the machine. Flg. l is a side new of the improved bit, Fig. 5 is a similar view of a modified form. Fig. 6 is a similar view of the cross drill bit now in common use.

The drill bits shown have shanks 0;. usually of octagonal form, and a series of four flaring wings 7) at the end of the bit. In the old form shown in Fig. 6, the V-shaped cut ting edges 0 all lie in the same plane at, right angles to the axis of the bit. The V- shaped edges 0 are formed with an upsetting dolly having straight V-grooves in its faces, and the operation of such a dolly tends to spread the thin metal edges and corners of the bit outwardly and tends to render the metal at the corners porous and spongy. That the metal is spread in this way is shown by the fact, that three or more resharpenings of the old form of drill bit will reduce the backs of the supporting wings, as indicated in clotted lines in Fig. 6, unless resort is had to extra upsetting.

The corners (Z of the bit are subjected to greatest amount of wear and with the ordinary form of bit made as described, these corners readily break, as indicated in Fig. 6, and the bits must be frequently resharpened.

In accordance with the present invention, the cutting edges on the wings are protuberant and preferably curved, as shown at ein Fig. 4. These edges may be polygonal, as shown at 6 1n Fig. 5. Either shape 18 made by acorrespondinglyshaped upsetting dolly (see Figs. 1 and having curved or other suitable shaped, cross V-grooves g in its face. The action of sucha dolly upsets the metal of the wings of the drill bit and compact-s the same along radial or converging lines, as indicated at e in Figs. a and 5. This compacting of the metal produces cross cutting edge portions in which the metal is more compact and homogeneous, and particularly at the corners, than in the old form of bit. Moreover, the angles between the cutting edges and the backs of the wings are obtuse; while in the 01d form shown in Fig. 6, these angles are acute. In the improved form there is, therefore, more metal at the corners to Withstand the great wear and strain brought to bear on these points.

The face of the dolly f is somewhat larger than the face of the bit and the grooves g are wider at the face of the dolly than the wing b of the bit. The grooves of the dolly face thus firmly engage the V-edges of the bit to properly shape the same, and, at the same time, the grooves tend to resist the lateral expansion of the metal at the corners (Z of the bit. This action tends to further compact the metal at the corners and assists in bringing the bit to proper size.

The upsetting dolly canbe caused to act upon the bit in any suitable manner. In the apparatus shown in Fig. 1, a steam or pneumatic hammer 7L mounted on a frame it is provided with a head if arranged to strike the dolly The latter is arranged to shift in a guide 7:: on the frame. The bit end of the drill rests on a support am having a seat m therein and a groove m to receive one of the wings of the bit. l/Vhen the dolly is in operation, the opposite end of the bit is placed against a suitable anvil to absorb the blow.

It is obvious that changes could be made from the details set forth without departure from the essentials of the invention as defined in the claims.

I claim as my invention 1. The method of shaping cross drill-bits which consists in forming centrally protuberant cutting edges upon the flaring wings of the bit by heating the same to soften the metal thereof, and simultaneously upsetting and compacting the softened metal of the Wings, While unconfined, along lines extending substantially at right angles to the protuberant cutting edgesand converging to the axis of the drill bit, substantially as described.

2. The method of shaping cross drill bits which consists in forming centrally protuberant, curved, V-shaped, cutting edges upon the flaring Wings of the bit by heating the 10 same to soften the metal thereof and simultaneously upsetting and compacting the softened metal of the Wings, While unconfined, along lines radial with respect to the curved cutting edges and converging to the axis of the drill bit, substantially as de- 15 Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

